Numeric, two-digit value of the day of the month.


The <day> element names a day of the month, in two-digit form as it would be stated as the “DD” in the international date format YYYY-MM-DD (for example, “03” for the third, “25” for the twenty-fifth).
Used in both the article metadata (<article-meta>) and within bibliographic references (<element-citation> and <mixed-citation>).
Related Essay: For a discussion on the use of <day>, see Dates in Citations.

Related Elements

Within citations (<element-citation> and <mixed-citation>), the elements <year>, <date>, <day>, <month>, and <season> may all be used to describe the date a cited resource was published. Other dates inside a citation, such as a copyright date, the date on which the author accessed the resource, or a withdrawal date, should be tagged using <date-in-citation> with the @content-type attribute used to name the type of date (copyright, access-date, time-stamp, etc.).


Content Model

<!ELEMENT  day          (#PCDATA)                                    >


Text, numbers, or special characters

This element may be contained in:

Example 1

In article metadata to record a lifecycle <history> date:
<contrib contrib-type="author">
<collab collab-type="committee">Technical Committee ISO/TC 108, 
Subcommittee SC 2</collab>
<fpage seq="1">1</fpage>
<date date-type="approved" iso-8601-date="2012-06-01">

Example 2

In article metadata, in both history and publication dates:
<article-id pub-id-type="pmid">...</article-id>
<aff id="StLukes">...</aff>
<pub-date publication-format="print" date-type="pub" 
<date date-type="accepted" iso-8601-date="2001-01-29">
<copyright-statement>Copyright &#x00A9; 1999, British
Medical Journal</copyright-statement>
<copyright-holder>British Medical Journal</copyright-holder>
<p>To examine the effectiveness of day hospital
attendance in prolonging independent living for
elderly people.</p>

Example 3

In an element-style bibliographic reference (punctuation and spacing removed):
<element-citation publication-type="book" publication-format="web">
<source>Fact sheet: AIDS information resources</source>
<publisher-loc>Bethesda (MD)</publisher-loc>
<publisher-name>National Library of Medicine
<year iso-8601-date="2002-05-02">2003</year>
<date-in-citation content-type="updated"
iso-8601-date="2005-07-14">updated 2005 Jul 14</date-in-citation>
<date-in-citation content-type="access-date"
iso-8601-date="2006-11-15">cited 2006 Nov 15</date-in-citation>
<size units="screens">[about 3 screens]</size>
<comment>Available from:

Example 4

In a mixed-style bibliographic reference (punctuation and spacing preserved):
<mixed-citation publication-type="book" publication-format="web">
<source>Fact sheet: AIDS information resources</source>
[Internet]. <publisher-loc>Bethesda
(MD)</publisher-loc>: <publisher-name>National
Library of Medicine (US)</publisher-name>;
<year iso-8601-date="2003-05-02">2003</year> <month>May</month>
<day>2</day> [updated <date-in-citation content-type="updated"
iso-8601-date="2005-07-14">2005 Jul 14</date-in-citation>;
cited <date-in-citation content-type="access-date"
iso-8601-date="2006-11-15">2006 Nov 15</date-in-citation>].
<size units="screens">[about 3 screens]</size>. Available from: